Machine for bending wood



(No Model.) 3 Sheets-Sheet 1.

A. HIRSHHEIMLER & G. M. MUELLER. MAGHINE FOR BENDING WOOD.

No. 426,641. 7 Patented Apr. 29, 1890.

U Cl C! U I l I l l wiinesses. Inveniovs.

' Hibert lhrshheimer 4'. C,71qrlS,m.muur

(No Model.) 3 Sheets-Sheet 2A.

A. HIRSHHEIMER & G. M. MUELLER. MACHINE FOR BE'NDING WOOD.

N0.-426,641. Patented Apr. 29, 1890.

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(No Model.) 3 Sheets-Sheet 3.

A. HIRSHHEIMER & O. M. MUELLER.

MAGHINE FOR BBNDING WOOD.

No 426,641. Patented Apr. 29,1890;

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MACHINE FOR BENDING WOOD.

SPECIFICATION forming part of Letters Patent No. 426,641, dated April 29, 1890. Application filed April 1, 1889. $eria1 No. 305,622. (No model.)

To all whom it may concern: T

Be it kn own that we, ALBERT HIRSHHEIMER and CHARLES M. MUELLER, citizens of the United States, residing at La Crosse, in the county of La Crosse and State of Visconsin, have invented certain new and useful Improvements in Machines for Bending food; and we do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and-to the letters and figures of reference marked thereon, which form a part of this specification.

This invention relates to improvements in mechanism for bending wood; and the object is, primarily, to apply the power in such a m anner and at such points that the fibers of the wood shall be compressed longitudinally at the same time and to the same extent that pressure is exerted in a lateral direction; in the construction and means for controlling the bed, and in the means for lifting the bent article and former from the brackets when the operation is completed, and, further in p the relative positions of the centers upon which the tilting brackets turn and the upright shoulders upon the same, by means of which the pressure is exerted upon the ends of the blank.

The, invention is an improvement upon the machine described in Letters Patent No. 391,794, granted to us October 30, 1888, (machine for bending staves,) and in the principal features of construction and arrangement are similar thereto.

Our improvements are illustrated in the ac companying drawings, in which- Figure 1 is a front view of the machine. Fig. 2 is a fragmentary side view, partly in vertical section, showing the yielding bed and the means for controlling the same. Figs. 3 and 4 are detail views of the blank-bending tilting brackets. Figs. 4 and 5 are details showing the relative positions of the centers and abutments Of the tilting brackets.

1 is the upright main frame, in which reciprocates vertically the presser-block 2, actuated by pitman connection with suitable the blank-supporting brackets 4 4. These brackets are so located that the presser-block shall be over the middle of the blank when resting upon the brackets. The brackets are substantially of the form described in our patent previously mentioned, with the excep-.

tion that a certain fixed relation between the position of the centers or upon which the tilting sections 5 5 turn, and the upright shoulders I) Z) upon the same, against which the blank abuts, is found to be of considerable importance in order that the bending may be accomplished perfectly without danger of slivering or otherwise parting the fibers of the wood. The centers should be so located with reference to the abutment, and the brackets should be so located upon the table, that the distance between the axis and the point e from which the shoulders rise and the distance apart of the two opposite abut ments when the beds upon which the blank rests are horizontal, and when, consequently, the said abutments are vertical, have such relation to each other that the former is equal to one-half the difference in length of the semi-circainference and the diameter of a circle having a semi-circun1ference equal in length to said last-named distance-that is, the distance between the two abutments, by which the end pressure is exerted when in normal position, being represented by a straight line, the distance between the axis upon which the bracket turns and the apex c of the angle formed by the abutment and the supporting-surface is equal to one-half the difference between the length of said line and the diameter of a circle whose semi-circumference has the same length as are also prevented. The pressure at the ends and in the center is always equal, exerted at the same time, and equally distributed throughout the whole length of the blank.

In the middle of the tableimmediately underneath the follower-die is mounted the yielding bed 6, having either a fiat or concave upper surface, according to the style of work to be done, and located upon the top of an upright bar mounted in suitable bearings firmly secured in the frame-work, so as to slide up and down therein. Around this bar, or otherwise connected with said bed in position to raise the same in its bearings, is a stiff spring 7, which acts normally to keep the said bed on a level with the supporting-surfaces of the brackets, so that when the blank is introduced under the die it shall rest evenly upon the three supports. The three partial supports are connected and the bed made continuous by means of arms 8 8, extending inwardly from the front of each tiltingbracket, as shown in Fig. 1, and entering recesses in the under side of the center bed 6 to assist in making the operation of thebed and brackets simultaneous when the blank is operated upon by the follower-die. As a modification of this construction,we have shown a strap of steel connecting the bed-surface of the two opposite tilting brackets and secured to them and to the bed. This construction is in some respects preferable, as a continuous yielding back is afforded for the blank, and in con uection with the evenly-distributed pressure obtained by this construction slivering is impossible.

For the purpose of bending staves we make use of the former described in our previous patent before mentioned. It is found, however, that the pressure upon the ends of the blanks exerted by the tilting brackets is so great as at times to make it diflicult to lift the former and blank off the brackets when the operation is completed. To obviate this difficulty we have attached to the front and back of the follower grappling-hooks 9 9, which, as the follower lowers, engage underneath the edges of the center bed in notches 1O 10, and which lift the same and the former carrying the stave therewith, releasingitfrom the'brackets. To render the operation of these grappling-hooks entirely automatic they are hinged at the front and back, respectively, of the follower, as shown, and suitable cams or their equivalent 11 11 are located upon the frame in position to release the same from engagement with the bed when it has risen high enough to free the former from the brackets and to allow the same to drop back into position to engage with the bed upon the downward movement of the follower. The most important function of the hooks, however, is to grip the bed 6 at the moment when pressure is begun to be exerted upon the blank by the downward move ment of the die, thus grasping the blank closely between the bed'and the former and preventing the bed from moving away from the blank as the pressure is increased. The bed is held closely up against the blank, even though the sprin may not be sufficiently strong to hold the same inplace of itself. The upper surface of the center bed (3 being concave in form when used for this class of work to correspond with the outside of a finished stave, the blank is thus firmlysupported at all points.

WVe claim as our invention 1. In a bending-machine, the brackets having blank-supporting surfaces, upright abutments upon said surfaces, pivots supported in bearings upon which said brackets are adapted to tilt, the said brackets being so constructed and located that the distance apart of the abutments of the two opposite brackets when in normal position, and the distance from the shoulder formed by the abutment and the supporting-surface to the axis upon which the bracket tilts, have such relation to each other that the latter is equal to one-half the difference in length of the semi-circumference and the diameter of a'circle having a semi-circum ference equal in length to said first-named distance, substantially as and for the purpose herein specified.

2. In a bending-machine, the follower-die, and means, substantially as described, for operating the same, tilting brackets mounted upon suitable supports at right angles to the path of said follower and at equal distances on each side thereof, each bracket being formed with a blank-supporting surface and abutment perpendicular thereto, the distance apart of the abutments of the two opposite brackets when in normal position, and the distance from the shoulder formed by the abutment and thesupporting-surface to the axis upon which the bracket tilts having such relation to each other that the latter is equal to one-half the difference in length between the semi-circumference and the diameter of a circle having a semi-circumference equal in length to said first-named distance, substantially as and for the purpose herein specified.

3. In a bending-machine, the follower-die, means, substantially as described, for actuating the same, tilting blank-supporting brackets supported'at equal distances on each side of the path of the same, yielding bed midway between said brackets, and connections between said brackets and yielding bed adapted to form a continuous support for the blank and distribute pressure uniformly thereupon, substantially as and for the purpose specified.

4. In a bending-machine, a presser-die, means, substantially as described, for actuating the same, tilting blanlesupporting brack ets located at equal distances on each side of the path of said die, abutments uponsaid brackets adapted to engage with the ends of the blank, yielding bed located in the path of said die, and a metal strap attached to said brackets and said yielding bed, substantially as specified, whereby a continuous yielding bed is formed for supporting the blank.

5. In a bending-machine, a follower-die, mean s, substantially as described, for actuating the same, tilting blank-supporting brackets located at equal distances on each side of the path of the said die, yielding bed in the path'of said die, and cam-operated grapplinghooks attached to andmoving with said die in position to grasp said bed when pressure is exerted upon the same by the movement of said die, substantially as and for the purpose specified.

6. In a bending-machine, a follower-die, means, substantially as described, for operating the same, tilting brackets having shoulders adapted to abut against the ends of the blank and located at equal distances upon each side of the path of said die, yielding bed in the path of said die cam-actuated grappling--hooks carried by said die, adapted to grasp said bed when pressure is exerted thereupon by the die, and to be released therefrom when the bed shall have returned to its normal position, substantially as and for the purpose herein set forth.

In testimony whereof we affix our signatures in presence of two Witnesses.

ALBERT HIRSIIHEIMER. CHARLES M. MUELLER. \Vitnesses:

HARRY MARSH, v F. XV. LANE. 

